A spheromak can be defined as a toroidal shaped arrangement of plasma consisting of electrons and ions. Traditional spheromaks contain large internal electrical currents and their associated magnetic fields are arranged so the forces within the spheromak are nearly balanced, resulting in confinement times of about a few microseconds without any external fields.
Spheromaks can be generated using a “gun” type device that ejects spheromaks off the end of an electrode into a holding area called a flux conserver. This has made them useful in the laboratory setting for analysis, and spheromak guns are relatively common in astrophysics laboratories. Spheromaks have also been observed to occur in nature as a variety of astrophysical events, like coronal loops and filaments, relativistic jets and plasmoids.
Spheromaks have been proposed as a magnetic fusion energy concept due to their confinement times, on the order of a few microseconds, which was on the same order as the best Tokamaks when they were first being studied in the mid-twentieth century. Though they had some successes, these small and lower-energy devices had limited performance.
It has been demonstrated that hotter spheromaks have better confinement times, and this has led to a second wave of spheromak machines. Spheromaks have also been used as a mean of injecting plasma into a bigger magnetic confinement experiment like a Tokamak. However, there remains a significant need for improvements in the generation of stable toroidal shaped particle assemblies for a variety of applications.